bpo-38858: Small integer per interpreter (GH-17315)
Each Python subinterpreter now has its own "small integer
singletons": numbers in [-5; 257] range.
It is no longer possible to change the number of small integers at
build time by overriding NSMALLNEGINTS and NSMALLPOSINTS macros:
macros should now be modified manually in pycore_pystate.h header
file.
For now, continue to share _PyLong_Zero and _PyLong_One singletons
between all subinterpreters.
diff --git a/Include/internal/pycore_pylifecycle.h b/Include/internal/pycore_pylifecycle.h
index 4e4bbc2..7292349 100644
--- a/Include/internal/pycore_pylifecycle.h
+++ b/Include/internal/pycore_pylifecycle.h
@@ -33,7 +33,7 @@
extern PyStatus _PyUnicode_Init(void);
extern int _PyStructSequence_Init(void);
-extern int _PyLong_Init(void);
+extern int _PyLong_Init(PyThreadState *tstate);
extern PyStatus _PyFaulthandler_Init(int enable);
extern int _PyTraceMalloc_Init(int enable);
extern PyObject * _PyBuiltin_Init(PyThreadState *tstate);
@@ -76,7 +76,7 @@
extern void _PyType_Fini(void);
extern void _Py_HashRandomization_Fini(void);
extern void _PyUnicode_Fini(PyThreadState *tstate);
-extern void _PyLong_Fini(void);
+extern void _PyLong_Fini(PyThreadState *tstate);
extern void _PyFaulthandler_Fini(void);
extern void _PyHash_Fini(void);
extern void _PyTraceMalloc_Fini(void);
diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index aa2103f..b78ed69 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -56,6 +56,9 @@
typedef PyObject* (*_PyFrameEvalFunction)(struct _frame *, int);
+#define _PY_NSMALLPOSINTS 257
+#define _PY_NSMALLNEGINTS 5
+
// The PyInterpreterState typedef is in Include/pystate.h.
struct _is {
@@ -139,6 +142,15 @@
int atbol;
} listnode;
} parser;
+
+#if _PY_NSMALLNEGINTS + _PY_NSMALLPOSINTS > 0
+ /* Small integers are preallocated in this array so that they
+ can be shared.
+ The integers that are preallocated are those in the range
+ -_PY_NSMALLNEGINTS (inclusive) to _PY_NSMALLPOSINTS (not inclusive).
+ */
+ PyLongObject* small_ints[_PY_NSMALLNEGINTS + _PY_NSMALLPOSINTS];
+#endif
};
PyAPI_FUNC(struct _is*) _PyInterpreterState_LookUpID(PY_INT64_T);
diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-11-21-09-02-49.bpo-38858.bDLH04.rst b/Misc/NEWS.d/next/Core and Builtins/2019-11-21-09-02-49.bpo-38858.bDLH04.rst
new file mode 100644
index 0000000..e489c94
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-11-21-09-02-49.bpo-38858.bDLH04.rst
@@ -0,0 +1,5 @@
+Each Python subinterpreter now has its own "small integer singletons":
+numbers in [-5; 257] range. It is no longer possible to change the number of
+small integers at build time by overriding ``NSMALLNEGINTS`` and
+``NSMALLPOSINTS`` macros: macros should now be modified manually in
+``pycore_pystate.h`` header file.
diff --git a/Objects/longobject.c b/Objects/longobject.c
index bc87fb2..be9301f 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3,6 +3,7 @@
/* XXX The functional organization of this file is terrible */
#include "Python.h"
+#include "pycore_pystate.h" /* _Py_IsMainInterpreter() */
#include "longintrepr.h"
#include <float.h>
@@ -15,12 +16,8 @@
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=ec0275e3422a36e3]*/
-#ifndef NSMALLPOSINTS
-#define NSMALLPOSINTS 257
-#endif
-#ifndef NSMALLNEGINTS
-#define NSMALLNEGINTS 5
-#endif
+#define NSMALLPOSINTS _PY_NSMALLPOSINTS
+#define NSMALLNEGINTS _PY_NSMALLNEGINTS
_Py_IDENTIFIER(little);
_Py_IDENTIFIER(big);
@@ -35,13 +32,6 @@
PyObject *_PyLong_One = NULL;
#if NSMALLNEGINTS + NSMALLPOSINTS > 0
-/* Small integers are preallocated in this array so that they
- can be shared.
- The integers that are preallocated are those in the range
- -NSMALLNEGINTS (inclusive) to NSMALLPOSINTS (not inclusive).
-*/
-static PyLongObject* small_ints[NSMALLNEGINTS + NSMALLPOSINTS] = {0};
-
#define IS_SMALL_INT(ival) (-NSMALLNEGINTS <= (ival) && (ival) < NSMALLPOSINTS)
#define IS_SMALL_UINT(ival) ((ival) < NSMALLPOSINTS)
@@ -53,7 +43,8 @@
get_small_int(sdigit ival)
{
assert(IS_SMALL_INT(ival));
- PyObject *v = (PyObject*)small_ints[ival + NSMALLNEGINTS];
+ PyThreadState *tstate = _PyThreadState_GET();
+ PyObject *v = (PyObject*)tstate->interp->small_ints[ival + NSMALLNEGINTS];
Py_INCREF(v);
#ifdef COUNT_ALLOCS
if (ival >= 0)
@@ -5782,7 +5773,7 @@
}
int
-_PyLong_Init(void)
+_PyLong_Init(PyThreadState *tstate)
{
#if NSMALLNEGINTS + NSMALLPOSINTS > 0
for (Py_ssize_t i=0; i < NSMALLNEGINTS + NSMALLPOSINTS; i++) {
@@ -5797,37 +5788,43 @@
Py_SIZE(v) = size;
v->ob_digit[0] = (digit)abs(ival);
- small_ints[i] = v;
+ tstate->interp->small_ints[i] = v;
}
#endif
- _PyLong_Zero = PyLong_FromLong(0);
- if (_PyLong_Zero == NULL) {
- return 0;
- }
- _PyLong_One = PyLong_FromLong(1);
- if (_PyLong_One == NULL) {
- return 0;
- }
-
- /* initialize int_info */
- if (Int_InfoType.tp_name == NULL) {
- if (PyStructSequence_InitType2(&Int_InfoType, &int_info_desc) < 0) {
+ if (_Py_IsMainInterpreter(tstate)) {
+ _PyLong_Zero = PyLong_FromLong(0);
+ if (_PyLong_Zero == NULL) {
return 0;
}
+
+ _PyLong_One = PyLong_FromLong(1);
+ if (_PyLong_One == NULL) {
+ return 0;
+ }
+
+ /* initialize int_info */
+ if (Int_InfoType.tp_name == NULL) {
+ if (PyStructSequence_InitType2(&Int_InfoType, &int_info_desc) < 0) {
+ return 0;
+ }
+ }
}
return 1;
}
void
-_PyLong_Fini(void)
+_PyLong_Fini(PyThreadState *tstate)
{
- Py_CLEAR(_PyLong_One);
- Py_CLEAR(_PyLong_Zero);
+ if (_Py_IsMainInterpreter(tstate)) {
+ Py_CLEAR(_PyLong_One);
+ Py_CLEAR(_PyLong_Zero);
+ }
+
#if NSMALLNEGINTS + NSMALLPOSINTS > 0
for (Py_ssize_t i = 0; i < NSMALLNEGINTS + NSMALLPOSINTS; i++) {
- Py_CLEAR(small_ints[i]);
+ Py_CLEAR(tstate->interp->small_ints[i]);
}
#endif
}
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 823d96e..4f05dfc 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -576,10 +576,11 @@
if (_PyStatus_EXCEPTION(status)) {
return status;
}
+ }
- if (!_PyLong_Init()) {
- return _PyStatus_ERR("can't init longs");
- }
+
+ if (!_PyLong_Init(tstate)) {
+ return _PyStatus_ERR("can't init longs");
}
if (is_main_interp) {
@@ -1251,7 +1252,11 @@
_PyList_Fini();
_PySet_Fini();
_PyBytes_Fini();
- _PyLong_Fini();
+ }
+
+ _PyLong_Fini(tstate);
+
+ if (is_main_interp) {
_PyFloat_Fini();
_PyDict_Fini();
_PySlice_Fini();